Machine tool structure and transmission mechanism



Dec. 16, 1952 J. B. ARMITAGE ETAL 2,621,566

MACHINE TOOL. STRUCTURE AND TRANSMISSION MECHANISM Original Filed Feb. 23, 1942 6 Sheets-Sheet l awe/whom JOSEPH B'RRM/TAGE 8- ORRIN WBRRKER W/MWW Dec. 16, 1952 J. B. ARMITAGE ETAL 2,621,566

MACHINE TOOL STRUCTURE AND TRANSMISSION MECHANISM Original Filed Feb. 23, 1942 6 Sheets-Sheet 2 nnmm lllllllllllllllll! W a IWHWIIYIIIIIIIIWIHNII" JOSEPH BflR E a:

x F- ORR /N W- RKER 4- 5% W am Dec. 16, 1952 J B, ARMlTAGE ETAL 2,621,566

MACHINE TOOL STRUCTURE AND TRANSMISSION MECHANISM Original Filed Feb. 23, 1942 6 Sheets-Sheet 3 JOSEPH B-HRMITRGE &

' ORR/N W-BRRKER Dec. 16, 1952 rr ET'AL 2,621,566

MACHINE TOOL. STRUCTURE AND TRANSMISSION MECHANISM Original Filed Feb. 23, 1942 6 Sheets-Sheet 4 11-11 mii Dec. 16, 1952 J. B. ARMITAGE ETAL 2,521,566

MACHINE TOOL STRUCTURE AND TRANSMISSION MECHANISM Original Filed Feb. 23, 1942 6 Sheets-Sheet 5 JOSEPH B-HRN/THGE& 5 ORR/N BARKER Dec. 16, 19 2 J. B. ARMITAGE ETAL ,5

MACHINE TOOL STRUCTURE AND TI/RANSMISSION MECHANISM Original Filed Feb. 25, 1942 6 Sheets-Sheet 6 JOSEPH B- RRM/TFIGE &

ORR/N w- BHRKER Patented Dec. 16, 1952 MACHINE TOOL STRUCTURE AND TRANSMISSION MECHANISM Joseph B. Armitage, Wauwatosa, and Orrin W. Barker, Milwaukee, Wis., assignors to Kearney & Trecker Corporation, West Allis, Wis., a corporation of Wisconsin Original application February 23, 1942, Serial No.

431,908, now Patent No. 2,407,913, dated September 17, 1946. Divided and this application June 24, 1946, Serial No. 678,818

8 Claims.

This invention relates, generally, to machine tools and more particularly to improved machine tool structure and operating mechanism of the type especially adapted for utilization in milling machines.

This specification constitutes a division of application Serial No. 431,908, filed February 23, 1942, that issued as Patent No. 2,407,913, dated September 17, 1946.

A general object of the invention is to provide improved structural arrangements and actuating mechanism for a machine tool;

Another object is to provide an improved power transmitting mechanism for actuating the movable elements of a machine tool;

Another object is to provide an improved speed changing spindle driving mechanism for a machine tool;

Another object is to provide an improved construction of the guiding means for supporting a movable element of a machine tool;

A further object is to provide an improved clamping arrangement for a movable element of a machine tool.

According to this invention, a milling machine is provided with an improved spindle driving mechanism arranged to afford a series of spindle speeds in two ranges. The speeds are selected by pick-off gears and a shiftable back gear, the pick-off gears effecting a direct connection in one range and a connection through the intermediate back gear in another. An interlock is provided to prevent the application of a pickoif gear at the position effecting the direct connection when the back gear is engaged and viceversa. Likewise, an improved arrangement is provided for supporting the spindle carrying head for vertical sliding movement and improved clamping means are provided for the head and for the overarms carried by the head.

The invention is exemplified herein by an embodying machine tool structure, but it is to be understood that the particular apparatus set forth is intended to be illustrative only and that the various individual characteristics may be embodied in other structural forms, all coming within the range of equivalents of the features defined in the subjoined claims.

The foregoing and other objects of this invention, which will be more readily discerned from the following detailed description, may be achieved by means of the illustrative apparatus depicted in, and described herein in connection with, the accompanying drawing in which:

Figure 1 is a general view in front elevation of a milling machine exemplifying the type of machine tool in which the present invention may be incorporated to advantage;

Fig. 2 is a view in side elevation of the milling machine shown in Fig. 1, with parts broken away;

Fig. 3 is a detailed view in perspective of a clamping device for the overarm structure of the milling machine;

Fig. 4 is a fragmentary view in perspective, showing the vertically movable spindle carrying head;

Fig. 5 is an enlarged fragmentary view partly in plan and partly in horizontal section, taken along the line 55 in Fig. 1;

Fig. 6 is another enlarged view in rear elevation of the milling machine with parts broken away to show internal mechanism;

Fig. 7 is an enlarged fragmentary view largely in vertical, axial section through. the spindlev carrying block, showing the spindle driving transmission mechanism;

Fig. 8 is a detailed view of the gear shifting mechanism in the spindle transmission;

Fig. 9 is a detailed view in perspective of the gear shifting yoke;

Fig. 10 is an expanded diagrammatic view of the spindle driving speed changing train; and

Fig. 11 is a view similar to Fig. 10 but with the gears shown shifted into another position.

Th particular machine tool illustrated in the drawing as exemplifying a practical embodiment of the principles of the present invention, is a milling machine of the bed type, similar in general form and arrangement of parts to the milling machine shown in United States Patent No. 2,118,357 issued May 24, 1938.

Referring more specifically to Fig. 1 of the drawing, the milling machine there shown comprises essentially a hollow bed or base 2E1 that constitutes the main supporting frame of the machine and forms a housing for the driving and controllin mechanism.

On the upper forward surface of the bed 28, a work supporting table 21 is slidably mounted for reciprocating movement longitudinally of the bed. At the rear of the table, a pair of uprights 22 and 23 are securely fixed to the upper surface of the bed 20 in spaced relationship and are joined at the top by a cap'24 to constitute a rigid upstanding column structure. As shown in Fig. 2, the column structure serves to support a rotatably mounted tool spindle 26 in co operating relationship with the work table 2!.

To provide for adjusting the position of the spindle 26 relative to the work table 2|, the spindle is carried by a spindle supporting head or block El which is slidably mounted between the uprights 22 and 23 for vertical movement. Adjustment of the vertical position of the spindle head is eifected by turning a combined hand wheel and nut 28 which abuts against the top of the cap 24 and has threaded engagement with a screw as the lower end of which is fixed in the spindle block 21, a graduated dial 30 being provided on the nut for indicating the amount of movement.

As best shown in Fig. 5, the spindle head 27' is provided at its sides with projecting, angularly disposed vertical guiding ways 32 and 33, respectively. The forward sloping surfaces of the angular ways have sliding engagement with complementary angularly disposed surfaces formed in the uprights 22 and 23. At its forward edge, the spindle block 21 is provided with laterally projecting lugs 35 and 35 which have sliding engagement with flat ways formed in a common plane on the forward faces of the uprights 22 and 23 respectively. The angular way 33 on the head is provided with a tapered adjusting gib 31 which may be tightened to effect accurate slidin engagement between the head and the uprights. As may readily be seen, when the gib 3? is tightened it moves into engagement with the complementary way in the upright 23 and draws the lug against the forward face of the upright. Simultaneously, the wedging action of the gib upon the angularly disposed sliding surface of the upright 23 forces the entire head 27 to the left and effects a similar wedging action between the sloping forward face of the way 32 and the plane face of the lu 34 upon the complementary surfaces of the upright 22, clearance spaces being provided between the other surfaces of the head and the uprights as indicated in the drawing. This arrangement provides for effecting close adjustment between the sliding head and the cooperating ways of the column structure, to insure accurate movement of the head. After the spindle head has been adjusted to bring the spindle 26 to the desired vertical position, by turning the hand Wheel 28, the head 2? may be locked to the uprights by tightening clamping bolts 38 which operate in T-slots 39 in the forward faces of the uprights and project through the lugs 34 and 35 of the head to clamp them against the forward flat Ways.

To provide for horizontal adjustment of the position of a cutter carried by the spindle 26, the spindle is rotatably supported, by means of anti-friction bearings ll and 52, in the ends of a cylindrical quill structure 43 which is slidably mounted for axial movement in the head 21, as shown in Figs. 2 and '7. Axial adjustment of the position of the quill is effected by turning a hand wheel 24 at the side of the upright 23, the hand wheel being operatively connected to the quill in well known manner and provided with a graduated dial 5 to indicate the longitudinal position of the spindle. After the spindle quill has been moved to an adjusted position, it may be clamped to the spindle block by turning a clamping nut '36 which draws a clamping element 41 into engagement with the quill, as shown in Fig. 7.

Above the spindle 2%, a pair of overarms 5| and 52 are slidably mounted in the spindle block 2'! in manner to extend forward to support a cutter carrying arbor, as shown in Fig. 2, the arms bein connected at their forward ends to the bed by means of a harness structure 53.

As best shown in Fig. 6, the upper part of the head 2'! is provided with a kerf 54 extending horizontally between the arm receivin bores to provide a resilient portion that may be deflected for clamping the arms. For this purpose, a clamping screw 55 is provided between the arms at each end of the head 21, the screws being fixed in the head beneath the kerf 54 by means of pins 55. Clamping nuts 51 are threaded on the upper ends of the screws 55 in manner to bear upon the top of the head and are adapted, when tightened, to deflect the upper portion of the head 27 downward into clamping engagement with the over-arms through partially closing the kerf 55. To provide for tightening the two clamping nuts simultaneously, each nut is fitted with an arm 58 the arms being interconnected by a link 58 pivoted at its respective ends to the end of each arm. As shown in Fig. 5, the forward nut 51 is provided with a wrench receiving hexagonal top by means of which both nuts may be tightened to clamp the overarms equally at both ends of the head. As best shown in Fig. 3, each nut 5! is provided with peripheral serrations which are engaged by complementary internal serrations in the cooperating arm 58. By reason of this serrated connection, each arm 58 may be adjusted angularly relative to its cooperating nut 51 in manner to equalize the clamping pressure exerted at the respective ends of the head 27. This arrangement provides for correcting any inequality which may result from wear between the nuts and the screws or the head, since the arms may be removed readily from the nuts at any time and re-engaged with the nut serrations at the position of adjustment providing for equal clamping pressures.

Power for moving the work table 21 and for rotating the cutter spindle 26 is derived from an electric motor BI mounted in the hollow bed 20, as indicated in Fig. 6, and connected by multiple belts 62 to a main drive pulley 63. For transmitting power to turn the tool spindle and to move the table at feed rate, the pulley 63 may be selectively clutched, under the conthol of a clutch lever F0 on the front of the machine, to a main drivin shaft H that extends through the bed to the front of the machine and serves to drive the table 2| as explained in the previously mentioned copending parent application, now Patent No. 2,407,913. Power for rotating the spindle 25 is taken from the main shaft H by means of a Worm 72 that is fixed on the shaft and has meshing engagement with a worm wheel '13 r0- tatably supported in the bed 28. The Worm wheel has splined connection with a vertically disposed splined shaft Id that is journalled in the spindle head 21 and arranged for vertical movement therewith, the splined connection with the worm wheel 13 providing a driving connection regardless of the vertical position of the spindle head. The vertical shaft 74 delivers power at constant speed to a bevel gear reversing mechanism 75 in the spindle head 2?, as shown in Fig. 7. For effecting reversal in the direction of spindle rotation, the reverser '15 may be actuated by a shifting arm is to provide for coupling the vertical shaft 14 to a horizontal power driven shaft Ti in manner to drive it in either direction for turnin the spindle in the one or the other direction, selectively.

From the horizontal power driven shaft H in the head 21, power is transmitted todrive the spindle at a selected rate in either of two speed ranges. When operating in the high speed range, power from the shaft 11 is transmitted by a pick-off gear 19 removably fitted on the end of the shaft, to a complementary pick-off gear 88 similarly fitted on the end of a parallel spindle driving shaft 8|, as shown in Figs. 6, 7 and 10. The shaft 8| is provided within the spindle head 2'! with a long pinion 82 that meshes with a large gear wheel 83 fixed on the spindle 26 in the rear of the quill 43, the arrangement being such that the gear wheel 83 may slide along the pinion 82 when the spindle and quill ar adjusted axially within the head 21.

As may best be seen by reference to Figs. 6 and 7, the pick-off gears 19 and 80 are mounted on the rear face of the head 21 and are protected by means of a hinged cover plate or door 84 which may be opened to provide access to the gear receiving ends of the shafts. Alternative sets of pick-off gears arranged to provide a series of spindle speeds, are stored in covered recesses 85 at the rear of the bed, as shown in Fig. 6.

For driving the spindle in the low speed range, there is provided a speed reducing or range changing intermediate or back gear mechanism arranged to transmit power indirectly from the power driven shaft 11 to the spindle driving shaft 8|. As may best be seen in the diagrammatic views, Figs. and 11, the intermediate speed reducing mechanism includes a shiftable pinion 81 that may be moved into meshing engagement with a complementary gear 88 on the spindl driving shaft 8|, as shown in Fig. 11, a shifting fork 89 being provided for this purpose. The pinion 81 has associated with it a gear wheel 90 which meshes with a long pinion 9| fixed on an intermediate shaft 92, the arrangement being such that the gear 90 may slide along the pinion 9| when the pinion 81 is shifted into or out of meshing engagement with the gear 88. The intermediate shaft 92 is provided at its end 93 with means for receiving a pick-01f gear 94 adapted to mesh with pick-off gear 19 on the driven shaft 11, as shown in Fig. 11. off gears transmitting power from the driven shaft 11 to the intermediate shaft 92 replace the pick-off gear direct driving connection between the shaft 1! and the spindle driving shaft 8| represented by the gears 19 and 8|! shown in Figs. 6, 7, and 10 in the drawing.

Since the driving mechanism would be locked, and injury might possibly result to the machine, if intermeshing pick-off gears should be applied to both the shaft 8| and the shaft 92 at the same time, means are provided for preventing the application of a pick-off" gear to the shaft 8| when the intermediate pinion 81 is meshed with the gear 88 for driving the shaft 8|. As shown in Figs. 8, 10, and 11 of the drawing, the shifting fork 89 associated with the pinion 81 is provided with an actuating rod 95 that extends through the rear wall of the head 21 into the pick-off gear compartment and is provided at its end with an actuating handle 96 which is accessible when the hinged door 84 is open, the arrangement being such that the handle 96 may be drawn outward to engage the intermediate drive and moved inward to disengage the drive. To prevent application of a pick-off gear to the shaft 8| when the pinion 81 is engaged with the gear 88, the shifting rod 95 is provided with an interlocking or interfering member 91 so arranged that it moves outward into the space otherwise occupied by the pick-off gear on the shaft 8| when the handle 98 is pulled out to en- The pair of pickgage the pinion 81 with the gear 88, as shown in Fig. 11, thus preventing a pick-off gear from being placed on the end of the shaft 8| while the intermediate speed reducing mechanism is engaged. Furthermore, this interlocking arrangement compels disengagement-of the intermediate drive when it is desired to operate in the high speed range with a pick-off gear on the shaft 8|. This is desirable even though no pick-off gear is applied to the shaft 92, since with the spindle driving shaft 8| operating in the fast range, the intermediate shaft 92 would be turned at excessive speed which would result in undue wearing of the mechanism. In the event that a pick-01f gear should be applied to the shaft 92 when operating in the high speed range, and meshed with either the pick-off gear '19 on the shaft 11 or the pick-off gear'88 on the shaft 8|, no harm would be done since, with the pinion 81 shifted out of mesh, this would result merely in turning the intermediate mechanism idly at moderate speed.

As appears in Fig. 7, lubricating fluid from a pump (not shown) is forced upward into the spindle head 21 through suitable connecting conduits I88, one of which discharges above an antifriction bearing I8 I, mountedin the rear wall of the head and serving to support the rearward portion of the spindle 28. The spindle is arranged to slide within the inner race of the hearing |8| when the quill 43 is moved longitudinally the bearing race being slidably keyed to the spindle to prevent relative rotation therebetween. From the bearing the lubricant drains through a passageway I92, onto a lip Hi3 from which it flows onto the pick-off gears 89 and 19 to lubricate them. Lubricant draining from the pick-off gears flows through a screened opening I84, into the lower part of the head 21 where it mingles with other excess lubricant draining from within the head. The lubricant collecting in the bottom of the head returns to a sump in the bottom of the machine bed through a telescoping tube 05 that constitutes a guard for the vertically disposed spindle driving shaft M.

The work supporting table 2| is driven to reciprocate in cooperating relationship with the tool spindle 26, by means of a feed screw I86 shown in Fig. 1, that is rotatably supported beneath the table in cooperating relationship with a stationary nut (not shown) fixed in the bed 28. The rate and direction of power movement of the table 2| may be controlled manually by actuating a lever l0! pivotally mounted on the front of the machine as is fully explained in the aforementioned parent application, now Patent No. 2,407,913.

From the foregoing detailed explanation of the operation of the exemplifying milling machine herein set forth as a practical embodiment of the present invention, it will appear that there has been provided an improved machine tool structure and actuating transmission mechanism that is especially adapted for convenient operation and that may be adjusted and maintained with facility.

Although the illustrative embodiment of the invention has been described in considerable detail for the purpose of fully disclosing a practical operative structure by means of which the invention may be practiced, it is to be understood that the particular apparatus herein described is intended to be illustrative only and that the various novelcharacteristics of the invention may be incorporated in other structural 7 formsawithout departing. from the spirit and scope of the inventionasdefined in the subjoined claims.

The principles of the invention having now been fully explained in; the-foregoing description of an illustrative embodying machine, we hereby, claim as our invention:

1. In a'machine to'ol, adriven working element, awsource of power; means for transmitting power from saidsource to said working element at aselected speed, said means comprising a shaft connected to be driven by said source of power "and adapted to receive a. pick-01f gear, a shaft connected to drive said working element and. adapted to receive a pick-off gear complementary to and meshing with the pick-off gear on said power shaft; an intermediate shaft adaptedtc-receive apick-oif gear to mesh with the 'pickwff' gear: on said power shaft, a speed changing: mechanism" selectively engageable to connect said intermediate shaft tosaid element driving shaft, and means associated with said speed changing'mechanism operatively disposed in the space normally occupied by the pick-off gear'when on' the driving shaft to prevent the application. of a pick-off gear to said element driving shaft whenever said speed changing mechanism. is connected to said intermediate shaft.

2. In a. machine tool power transmission mechanism, the combination with a driven memher and asourceof driving power, of a speed changing gear train disposed to connect said source of power to said driven member to drive it at selected speed, said gear train comprising shiftable gearing and interchangeable gearing, and an interlocking mechanism associated. with said shiftable gearing and said interchangeable gearing and shiftably disposed in the space normally occupied by certain of said interchangeable gearing to prevent application of certain of said interchangeable gearing when said shiftable gearingis in a predetermined one of its positions.-

3. In a machine tool having a driven working element; means for driving said'element at selected sp'eed'including a pick-01f gearchanging mechanism and. a. selectively engageable speed changing: mechanism .said mechanisms being alternatively operable, andian interlocking means operatively disposed to move into and out of the space normally occupied by certain of said pickoff gearing to prevent application: of a pick-off gear when saidselective speed" changing mechanism is engaged and to prevent engagement of said selective speed'changing mechanism when said pick-01f gear mechanism iscperating.

4. In a machine toolsupport driving mechanism, adriven shaft adapted to receive a pickoff gear, another shaft arranged to receive a complementary pick-off gear, means operatively connecting said second shaft with the support.

mounted on said'element,..a first: power'driven shaft rotatably mounted on said element onanaxis parallel to and spaced from the spindle axis, an intermediate shaft rotatably mounted on said element, a gear'connection between said intermediate shaft and" said spindle, said first power driven shaft and intermediate shaft having projecting ends arranged to each receive one of a pair of pick-01f gearsto form a. direct drive between said first power driven shaft and the intermediate shaft to complete the transmission for one spindle speed, a: second shaft disposed in parallel relationship with said first and intermediate shafts said second. shaft .having one end arranged to receive one of a pair of pick-off gears for cooperating relationship with a mating pick-off gear on said first power driven shaft, and backsgear mechanismconnect ing said second shaft with said intermediate shaft whereby a transmission is completedv to drive said spindle at a speed in a different range from said first named speed.

6. A milling machine transmission comprising a spindle block, a quill mounted for axially slidable movement in theforward wall of said spindle block, a spindle having its forwardend rotatably journalled in said quill and its opposite end rotatably journalled for axially slidable movement in the rear wall of said block, a spindle drive gear affixed tosaid spindle between said'spindle block wall and said. quill, said spindle, quill and drive gear being axially slidableasione'unit, a gear traincomprising a variable speed transmission connected to drive said spindle: in any of its axially adjusted positions;.shiftable gearing in. said gear train providing a selective driving connection'to obtaineither of two separate speed ranges, interchangeable gearing in said g'ear train arranged for selective application in either of said separate speed ranges, and'an interlocking mechanism: operatively' disposed to impinge upon the position normally occupied by certain of said interchangeable gearing and thereby prevent the application of l certain of said interchangeable "gearing when said shiftable gearing'is in predetermined one of itspositions;

'7. In a power transmission mechanism for driving a rotary element of a machine tool, a

source or" rotary power, shiftable speed changinggearing selectively engageable to drive said rotary machine element, pick-off gearing selectively applicable to transmit power at selected speed ratio from said source of power either directly to said rotary element or to said shiftable speed changing gearing, and interlocking mechanism associated with said speed changing gearing andoporative in the space normally occupied by'certain of said pick-off gearing to prevent application of pick-off gearing directly to said rotary element while said speed changing gearing is engaged to drive said element and to prevent engagement of said speed 'changinggearing while said pick-off gearing is applied to drive said element directly.

8. In a compactly constructed variable speed transmission mechanism, a spindle block having forward and rear Walls, a quill mounted'for rotatably journalled in said quill andthe 0pposite end rotatably journalled. in the rear wall.

of said spindle block, a driving gear affixed to $5161 spindle between said 'quill and: said rear.

jspindle block wall, means for movingithe. uni- 9 tarily slidable structure formed by said quill spindle and drive gear, a primary shaft rotatably journalled in said block on an axis parallel to said spindle and in constant driving engagement with said spindle drive gear, a power shaft rotatably journalled in said block on an axis parallel to said spindle, interchangeable pick-off gears arranged for application to gear receiving ends of said power shaft and said primary shaft for driving said spindle at selectively varying speeds in one speed range, an intermediate shaft rotatably journalled on an axis parallel to said spindle and provided with a gear receiving end, and shiftable gearing arranged to effect a selective driving connection between said intermediate shaft and said primary shaft and simultaneously prevent application of one of said pickoff gears to said primary shaft, whereby a second speed range is obtainable and said interchangeable pick-off gears may be applied to the gear receiving ends of said intermediate shaft and said power shaft for driving said spindle at selectively varying speeds.

JOSEPH B. ARMI'IAGE. ORRIN W. BARKER.

10' REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Number 

